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Vascular smooth muscle cell calcification and SLC20 inorganic phosphate transporters: effects of PDGF, TNF‐alpha and Pi
Author(s) -
VillaBellosta ricardo,
Levi Moshe,
Sorribas Victor
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.lb67
Subject(s) - vascular smooth muscle , platelet derived growth factor receptor , endoplasmic reticulum , calcification , pi , cell , microbiology and biotechnology , pdgfb , biology , chemistry , endocrinology , medicine , biochemistry , growth factor , receptor , smooth muscle
Pi transport by vascular smooth muscle cells (VSMC) has been proposed to play an important role in the pathogenesis of vascular calcification. In this study we have determined the correlation between calcification induced by Pi, PDGF‐BB, and TNF‐alpha and the expression of Pi transport in rat VSMC. These agents induced calcification and increased the expression of Cbfa1, Msx2, and Bmp2 RNAs in rat aortic VSMC, while Pi transport rate was not modified per milligram of protein. Only PDGF increased Pi transport when it was expressed per unit of DNA, as PDGF also increased total cell protein by 100 %, while DNA content was not modified. PDGF increased the expression of the Pi transporter, Pit‐1, but membrane protein biotinylation showed that Pit‐1 abundance was not modified in the cell surface. Immunofluorescence revealed that Pit‐1 is only slightly expressed at the cell membrane, but strongly expressed inside the cell, whose signal colocalizes with endoplasmic reticulum (ER) markers. PDGF increases Pit‐1 expression in the ER but not the plasma membrane.